What's a Cluster?

Cluster sets are sets with built-in, short rest periods of 5-20 or so seconds. They allow for creative manipulation and combinations of volume and intensity. Yep, that covers it.

Clusters for Size

Training volume is needed for growth. The amount, however, depends on the individual. Some freak shows seem to just touch weights and grow. Others (i.e., the rest of us) need more volume and more calories.

Consult materials from any training certification governing body and you'll find rhetoric about sets of 8-12 with 70-80 percent of one-rep maximum. Volume-wise they're not far off – 4 sets of 8 supplies 32 reps; 3 sets of 12 gives us 36. For a big lift that's trained hard, this is sufficient growth volume. Intensity-wise, however, these protocols are steeply lacking.

High-threshold motor units – the ones best suited for hypertrophy – are best recruited at high training intensities, accompanied by greater motor unit synchronization and greater muscular force. The requisite muscular tension needed for successfully completing a higher-intensity lift sends the message to the brain to bring out the big guns. (As always, we return to the nervous system.)

This happens, too, during straight sets, but only as fatigue is reached. Cluster sets allow for motor unit synchronization, high levels of muscular force, and the recruitment of high-threshold motor units without fatigue. Heavier weights for more reps, gives us bigger muscles.

Think also about the metabolic disturbance created by session density. Since rest periods are easily manipulated while working at higher relative intensities, more load is handled in a shorter amount of time. As rest periods are cut there is a big metabolic disturbance. That's why you often hear growth hormone likes heavy weights and little rest.

Size Cluster Strategy

We need to build volume and stress while maintaining intensity, so we'll build our size clusters using doubles and triples. Intensity, however, remains relatively constant – volume and rest are manipulated to elicit a training effect.

Week Sets Cluster Reps Rest Intensity Rest - Sets
1 4 2-2-1 * 15 sec. 7-8 90-120 sec.
2 4 2-2-2 * 15 sec. 7-8 90-120 sec.
3 5 3-2-2 * 15 sec. 7-8 90-120 sec.
4 4 3-3-2 * 10 sec. 7-8 90-120 sec.
5 4 3-3-3 * 10 sec. 7-8 90-120 sec.
6 5 3-3-3 * 10 sec. 7-8 90-120 sec.

* The dash signifies the rest taken between clusters.

During the last week of this progression, 45 reps are completed at a high intensity in eight and a half minutes. That's enough stress and density to make anyone grow.

This strategy works for main lifts and first level accessory movements. Be sure, though, not to accumulate too much fatigue during your main lift if you plan on using this progression to load your assistance move. If you do, loading won't be intense enough and you'll poop out before getting the desired effect.

What about the straight sets? While they may still work, you'll want to bump them to your secondary exercises with this setup, keeping the reps between 5-8. Progress up to 4 sets of 8 reps or 5 sets of 5. You'll get plenty of volume with appropriate intensity.

A warning though: you'll feel like hell at the end of this cycle. But you'll grow. A lot.


Clusters for Strength

Everybody wants to move daddy weight. I have a hunch that's why Westside's gotten so popular. Who doesn't want to max out every week?

Of course, Westside produces results – especially for geared lifters – but twice per week max outs are enticing. It worked for me for years.

Over the years, though, the continual maxing raised some questions. Why does my shoulder hurt? Is that my spleen coming out of my arse? And an even better question, did I get all that I could have out of that weight?

Strength is the result of neurological output. That's why lifters at Westside are constantly rotating exercises (which are more similar than they are different) on their max-out days. These guys (and gals) are so neurologically efficient that their output is greater than most lifters. They're getting all that they can out of a load.

I'm not a Westside lifter – I'm just a dude that's kind of strong that wants to get stronger. I presume that you and I are similar – our outputs don't match that of David Hoff. There are a lot of other variables that cloud the argument, but the main point is simple – most lifters need to master building tension, technique, and force with a given load before adding more plates to the bar.

Clusters, used in place of a first assistance exercise, fund the solution to this quandary.

Strength Cluster Strategies

Strength clusters differ from size clusters in a few ways. Sure, you'll still match volume and intensity appropriate for mass gain, but progression and sequence change.

Rather than increasing volume and decreasing rest intra-set, we'll hold each variable constant. To boost strength, we'll increase load and place the clusters secondary to the main loading parameter of the main lift. Essentially we're extending the main exercise and using clusters to keep the intensity constant. Have a look.

Week Sets Cluster Reps Rest Intensity Rest - Sets
1 1 2-2-1 15-20 sec. 8 150-180 sec.
2 2 2-2-1 15-20 sec. 8-9 150-180 sec.
3 3 2-2-1 15-20 sec. 8 150-180 sec.
4 1 2-2-1 15-20 sec. 8 150-180 sec.

As an example, we'll use the overhead press. You'd complete straight sets to load the overhead press–four sets of three of an intensity about 8 or 9. Once you complete the straight sets, complete the normal rest period and then begin the clusters. The goal is to use the weight you used for your straight sets, or just slightly less.

Although the mass cycle above is six weeks, I don't write concerted strength programming for more than four weeks at a time. Loading is too intense so things must be monitored with a keen eye.

We'll use 2 reps for the first two clusters and 1 rep for the last. This allows for appropriate time under tension – a max lift is going to take more than one second. It helps to simulate that from time to time. The single for the last cluster ensures that we limit fatigue and nail a solid final rep.

Again, this scheme is subsequent to your intense, main lift loading – sets of 2-5 at about 8 or 9 intensity. A little rest before starting the clusters is a good idea.

Clusters for Technique

Most lifters aren't good lifters. There's an illusion that there are a lot of good lifters out there, when really we're exposed to the top 10 percent through the Internet. Perhaps it's that whole mom thinks I'm special deal again. Either way, the vast majority are poop. Sorry for the pessimism, but progression depends on reality.

Truth is, we could all use technique work. Instead, though, most of us rush into the next exercise thinking that assistance work is always the answer. I'm as guilty as anyone else.

Assistance work is important for overcoming deficits, but it's only an accompaniment to improving technique. Just as we have a need for continued tension and output at a given weight, we need practice at lifts we want to be great at.

Technique Cluster Strategies

Get set, execute, complete and then reset – it sounds like football practice. Lifting is analogous; when working technique, short periods of intense focus are necessary. Intermittent breaks in focus promote a powerful reset.

Rather than envisioning technique clusters' volume as sets and reps, we approach it through time. And instead of using the doubles and triples in the previous cluster strategies, technique clusters are extended sets of singles.

Here's a visual.

Intensity Reps Duration Rest
7 1 10 min. At least 15 seconds between singles

In other words, the goal is to do 1 rep every 15 seconds for 10 minutes. However, the rest increases as the rep speed or rep quality decreases.

The intensity of about 7 permits ample volume to be built over the 10 minute set duration while providing enough load so that time isn't wasted. Taking at least 15 seconds between singles gives us a mental reset and limits fatigue. Again, start by resting exactly 15 seconds, but if fatigue accumulates and bar speed slows, increase the rest until speed is restored.

Progress by increasing either intensity or set duration. I'm apt to increase set duration first, allowing for more practice volume. Twenty minutes is my cut off – after 20 minutes fatigue accumulates and focus deteriorates. Using the same movement as you did for your main exercise, plug these clusters in between your main lift and your first level assistance exercise.

They can be used as main exercise loading, but they aren't as effective. We want to extend the use of an exercise to improve technique – it makes the most sense to use them as secondary loading after the main lift was loaded heavily.

Which Lifts?

In theory, I suppose, that cluster sets are employable for any lift. But a lot of things are said in theory. Sasquatch is a good example. Theoretically, it's possible that there's an eight-foot ape-man that smells like smoked grundel and Indian food marauding through the bush. Good sense, however, leads me to believe otherwise.

I've experimented with loading a lot of exercises with cluster sets – curls, skull crushers, lunges and push-ups. I've found, however, that clusters are best done with a heavy barbell on the back or in the hands.

Anything less than a barbell is subpar for creating the intensity necessary for successful cluster loading. But please, squat, deadlift, press and bentover row to your heart's content.


Bigger, stronger and better – clusters provide a means to each. I know, it sounds like a saying from a cheesy fitness meme. However, rather than filling you with hype and sensationalized motivation, clusters fill your program with progress.